MLA

Peter, of Blois, approximately 1135-approximately 1212. Peter of Blois. [between 1450 and 1500]. https://collections.library.yale.edu/catalog/10965981.

APA, 6th edition

Peter, of Blois, approximately 1135-approximately 1212. ([between 1450 and 1500])[Peter of Blois]. https://collections.library.yale.edu/catalog/10965981.